Heat exchanger



A. F. HOESEL HEAT EXCHANGER Jan. 22, 1935.

2 Sheets-Sheet 1 Filed Feb. 5, 1952 VIII/1 7 1 [NW-N701? ANTHOMf/fOESfL Arrow/[rs Jan. 22, 1935. A, F, HOESEL 1,988,494

HEAT EXCHANGER Filed Feb. 5, 1952 2 Sheets-Sheet 2 [mam/ 02 ANTHONY 1?",150255L F M M A TTOR/VEYS 10 unit;

Patented Jan. 22, 1935 v UNITED STATES 1,988,494 HEAT EXCHANGER Anthony F. Hoesel, Chicago, 111., asslgnor to Charles C. Kritzcr, Chicago, 111.

Application February 5, 1932, Serial No. 591,086

10 Claims.

My invention relates to refrigeration, and in- I eludes among its objects and advantages the provision of an improved cooling unit. In the accompanying drawings: Figure 1 is a diagrammatic view illustrating a cooling unit according to the invention; v

Figure 2 is an end elevation of the unit shown in Figure 1;

Figure 3 is a detail view of a Figure 4 is a diagrammatic view illustrating a step in the fabrication of the unit;

Figure 5 is an enlarged detail view illustrating the method of assembling and fastening fins 15 upon a conduit;

Figure 6 is an enlarged sectional view of one of the fins;

Figure '7 is a plan view of one of the fins;

Figure 8 is an end view of a strengthening bar associated with the fins;

Figure 9 is a side elevation of the structure shown in Figure 8;

Figure 10 is a view similar to Figure 8 showing a different form of bar;

Figure 11 is a diagrammatic end view of a cooling unit showing the groups of fins tied together by means of the bar shown in Figure 10.

Figure 12 is a different form of fin construction; and 30 Figure 13 is a sectional view of the fin shown in Figure 12.

In the embodiment selected to illustrate the invention; I make use of a pipe or conduit 10 upon which a plurality of sheet metal fins 12 35 is mounted and arranged in groups 14. The

groups are spaced apart sufiiciently far to permit the pipe to be bent at 16 for nesting the groups in parallel relation, thereby defining the contour of the cooling unit when the latter comprises more than one group, as shown in Figure 1. In this figure, I have shown the ends of the cooling unit as comprising supporting plates 18. The bends 16 are passed through slots 20 in the plates 18 (see Figure 3) and secured to the plates by welding. In addition to supporting the groups 14 in rigid asembly, the plates 18 are formed of thin sheet material and function as cooling fins in the same way as the fins 12. The cooling unit shown in Figures 1 and 2 comprises four groups of fins arranged in nested relation. Any -number of groups may be embodied in a unit by merely assembling the requisite number of fins upon the pipe.

In Figures 6 and 7, I have shown one of the 55 fins separate from the conduit. The fin is proportion of the vided with a central opening 22 for receiving the pipe 10. The original diameter of the opening is slightly less than the diameter of the pipe. In Figure 6, the lines 24 indicate the diameter of the pipe 10 with respect to the original diameter 5 of the openings 22. After the openings 22 have been punched in the fins, the material surrounding the openings is distorted or dished to provide conical portions 26. Such dishing of the fins increases the diameter of the openings to the ex- 10 tent that the pipe will pass freely through the openings, whereby the fins may easily be assembled upon thepipe.

It will be noted that the surface 28 defining the opening 22 (see Figure 6) retains its rightangular alignment with respect to the surface of the distorted area, as indicated by the angles 30.

I have found that the original diameter of the openings 22 may be 1/64th of an inch less than the pipe diameter when the latter is A; inch. After dishing, the diameter of the openings 22 will be approximately 1/64th of an inch greater than the inch pipe diameter. These relative dimensions will of course vary with difierences in the pipe diameters and the specific fin construction, particularly the gauge of material used for the fins.

After assembling the fins upon the pipe 10, the fins" are firmly secured to the pipe 10 by deforming the previously distorted area a sec- 30 0nd time. This is accomplished by positioning the apex of the dished portion 26 adjacent an abutment 32 and striking the fin upon the opposite side with a plate-like member 34. Thus, the fin between the abutment 32 and the striker 35 plate 34 (see Figure 5) is shifted from the full line position to the dotted line position. Returning the dished area to a plane substantially normal to the fin proper causes a contraction of the opening 22 upon the pipe 10 to such a degree that the fin will be firmly fixed upon'the conduit. Since the surface 28 retains its original angular relation with the sides of the fin after the dished portion has been pressed back to normal, the entire surface 28 will have firm frictional contactwith the pipe, so that the joint affords maximum conductivity. At the same time, the fins will be positioned in perfect alignment at right-angles to the longitudinal axis of the conduit. My construction entirely eliminates the necessity for spacers between the fins, and permits the use of a single piece of pipe regardless of the length required.

An alternative fin construction is illustrated in Figures 12 and 13. In this form, the fin 46 is provided with a corrugation 48 concentrically arranged with respect to the transverse axis of the fin. The corrugation is stamped in the fin before the opening 50 is out. In Figure 13, I have indicated theopening 50 as having a diameter slightly larger than the lines 52 which indicate the relative diameter of the tube. This fin differs from the fin previously described in that the fin is distorted before the opening is cut, and the opening is cut with an original diameter slightly greater than the tube diameter. v

After the fins 46 have been mounted upon the tube, the fins are firmly secured to the tube by pressing the material defining the corrugations back to normal. The flattening of the corrugations reduces the diameters of the openings 50 to such an extent that the fins will be firmly fixed upon the tube. The same type of abutment and striker plate may be employed in depressing the corrugated construction as are used in connection with the first described fin.

A cooling unit made up of a single piece of tubing eliminates joints which may leak and permit the escape of gas. Furthermore, the onepiece construction eliminates the necessity for welding a large number of joints. The bends 16 are easily insertable into the slots 20, and the ends of the pipe 10 are provided with fittings 36 for connection with conduits (not shown) associated with the cooling unit after they have been passed through openings in the plates 18.

In Figure 8, I have shown the fins 12 as being provided with slots 38 in each of their corners. One bar 40 may be associated with each group by driving it into the aligned slots in a predetermined corner of the group. This bar reenforces the unit against sagging in the middle, thus permitting the construction of relatively long units from small diameter or thin walled tubes. A bar may be associated with each corner if the construction of a specific unit requires added reenforcement. No such reeniorcement is necessary in the ordinary construction.

In Figure 10, I have illustrated a modified form of bar construction. In this form, I employ a V-bar 42 designed to connect two groups of fins together in rigid relation. The normal crosssectional shape of the bar is illustrated in dotted lines at 44. In this collapsed condition, the edges of the bar are substantially aligned with the slots in the two groups and may be driven into the slots in the two groups simultaneously. The bar is constructed from a thin metal having the necessary flexing properties to permit the bar to spread as it is being driven home. The groups are movable relatively to each other within certain limits by reason of the flexible character of bent tube construction, thereby providing spacing compensation which facilitates placement of the V-bar.

Figure 11 is a diagrammatic illustration, of a cooling unit comprising sixteen groups tied together by a plurality of the V-bars 42. The specific arrangement of the bars in the unit is determined by the method of bending the tube 10. The arrangement shown in Figure 11 is a good one in cases where the groups are arranged in parallel relation by bending the pipe in the order indicated by the numerals one to sixteen inclusive on the groups.

Without further elaboration, the foregoing will so fully explain my invention that others may, by applying current knowledge readily adapt the same for use under various conditions of service.

I claim:

1. In a heat exchanger a one piece finned tube bent to provide a plurality of banks of fins arranged in nested grelation with their tube reaches in parallelism, the portions of the tube between said reaches being U-shaped, said fins being rectangular in contour with their corners axially aligned, said fins having recesses in their corners, a plurality of strips lying in said recesses and tieing the fins in each bank into a rigid assembly and defining the corners or said banks, and a pair of plates defining the ends of said heat exchanger, said plates having openings to receive the U-shaped bends of the tube and openings to receive the end portions of the latter, said strips having their ends fastened to said plates.

2. A heat exchanger comprising a one piece finned tube bent to provide a plurality of banks of nested fins having their tube reaches arranged in parallelism, the fins being rectangular in contour with their corners axially aligned and having notches in their corners, and a bracing strip arranged to be driven into the aligned notches in two adjacent banks for tieing the fins in each bank into a rigid assembly and interconnecting said banks in pairs;

3. In a heat interchanger, a plurality of units, each unit comprising a reach of tubing, a plurality of polygonal fins on said reach with their corners axially aligned, said fins having notches in their corners, and a plurality of longitudinal g'uard braces entered in said aligned notches, said interchanger comprising a plurality of units arranged with their tube reaches in parallelism, and cover plates at the ends of said heater common to a plurality of units and united with a plurality of said longitudinal braces; the reaches of certain of said units being spaced apart portions of a one-piece tube, the portions of the tube between the units being bent into a U-shape to bring the reaches side by side and parallel.

4. A heat exchanger coil comprising a tube having two groups of spaced fins mounted thereon, said tube being bent between said groups to arrange the latter with their ends in common planes, and end plates, one of said end plates having a slot for receiving the bent portion of the tube, the other endplate having holes for receiving the tube. I

5. A heat exchanger unit comprising a tube having two groups of fins mounted thereon in spaced relation, said tube being bent between said groups to arrange the groups in parallel relation with their ends terminating substantially in common planes, the ends of said tube extending beyond said groups, and a pair of end fins substantially coextensive with the end areas of said groups, one of said end fins being slotted to receive the bent portion of the tube and the other of said end fins having holes for receiving the ends of the tube, and a brace bar at each of the four outer corners of the assembly for connecting the groups and the end fins into a rigid assembly.

6. A heat exchanger unit comprising a onepiece conduit having a plurality of groups of fins mounted thereon in spaced relation, said tube being bent between said groups to arrange the same in stacked relation, a plurality of bars connecting the groups into a rigid assembly,

each of said bars being connected with the fins in two adjacent groups; a pair of end plates, said end plates being slotted to receive the bent portions of said tubes, and a bracing bar at each corner of the nnit'ior connecting the end plates and the fins defining the corners of the assembly into a unitary whole.

7. In a device of the type described, a conduit shaped to provide a plurality 01' reaches in nested relation, a group of spaced fins mounted upon each reach, and a plurality of bracing bars, each bar being connected with two groups 01' finsior tying the assembly into a unitary whole.

8. A, heat transfer apparatus comprising a plurality oi relatively fiat fin plates in spaced parallel relation, each fin plate having a single aperture to receive a conduit, the openings in said fin plates being in axial alignment, and a conduit passing through said openings and having frictional engagement with eachfin plate, a plurality of series of such fin plates arranged in parallel nested relationship with the ends of all the series terminating in substantially the same plane, and longitudinal'braces interconnecting and bracing edge portions of each series of fin plates to prevent interval or rotary displacement of any individual fin plate, said longitudinal braces also interconnecting edge portions of fin plates in adjacent series to brace and rigidity the nested whole; the conduits passing through each series constituting portions oi a-single one-piece tube passing through all the series of the nested whole; end plates co-extensive with the transverse dimensions of the nested whole, said end plates having slots .to receive the bights oi the one-piece tube, the

ends of said longitudinal braces being fixedly united, as'by riveting, with said-end plates to unite the nested whole into a rigid unitary structure; one oi said longitudinal braces extending along each oi the corners of the completed, nested whole;

9. A- heat exchanger. coil comprising a tube having groups of spaced fins mounted thereon, said tube being bent between said groups to arrange said groups on parallel reaches of the tube with the ends of the group in common planes, and end plates, one of said end plates having slots for receiving the .bent tube portions at'that end of the coil, and other end plate having differently positioned slots for receiving the bent tube portions at the other end of the coil. 1

10. A combinationaccording to claim 9 in which at least one of the end plates is also cut away to provide clearance for the e or a straight tube end. 7

a ANTHONY F. HOESEL. 

